MEXICO CITY – Three police officers and four inmates died in a shootout during an inspection at a prison in Ciudad Victoria, the capital of the northeastern Mexican state of Tamaulipas, state security officials said on Wednesday.

“Three policemen and four inmates died. Wounded, six policemen and seven inmates,” the Tamaulipas Security Secretariat said in a Twitter post.

A riot broke out at the prison in Ciudad Victoria on Monday after police entered the facility to conduct an inspection.

State police officers were sent to the penitentiary after prison officials detected rising tensions in the facility and suspected that banned items had been smuggled in.

The operation, which continued late into the night on Tuesday, included Federal Police and army units, which cordoned off the prison.

Mexican media outlets broadcast reports on which long volleys of gunfire could be heard.